Anti-friction latchbolt

ABSTRACT

A latchbolt assembly includes a solid latchbolt having at least a first surface, a second surface and a third surface and an anti-friction bolt pivotally coupled to the solid latchbolt. The anti-friction bolt includes a cross member disposed adjacent the first surface of the solid latchbolt and a pair of plates depending from the cross member to form a U-shaped cross section. The plates are disposed adjacent the second and third surfaces of the solid latchbolt.

The present invention relates to latchbolts in general and anti-frictionlatchbolts in particular.

BACKGROUND OF THE INVENTION

Various means have been used to reduce friction on latches. One reasonfor this effort is to minimize wear on the latch. Another reason is tominimize the likelihood that a door will not fully close, therebyleaving a room susceptible to unauthorized access.

Past efforts illustrated in FIG. 1 typically include a latchbolt havinga first portion 10 with two fingers 12 extending longitudinally from abase portion 14 forming a yoke and a second portion 16 pivotally mountedbetween the two fingers 12. Such latchbolts are typically installed inmortise boxes having a front plate through which the latchbolt extendsto engage a strike installed in the doorjamb.

The second portion 16 includes a shoulder 18 extending therefrom in thedirection of the closing action of the door. As the door closes, thesecond portion 16 engages the strike and is thereby pivoted between thetwo fingers 12. As the second portion 16 pivots, the shoulder 18 engagesthe inner surface of the front plate, thereby beginning the retractionof the latchbolt into the mortise box before the two fingers 12 engagethe strike.

Past efforts have proven to be weak and lacking in durability. Thepresent invention overcomes these disadvantages by providing an outsideanti-friction bolt that is stronger and more durable than conventionalanti-friction bolts.

SUMMARY OF THE INVENTION

A latchbolt assembly includes a solid latchbolt having at least a firstsurface, a second surface and a third surface and an anti-friction boltpivotally coupled to the solid latchbolt. The anti-friction boltincludes a cross member disposed adjacent the first surface of the solidlatchbolt and a pair of plates depending from the cross member. Theplates are disposed adjacent the second and third surfaces of the solidlatchbolt. In preferred embodiments, the latchbolt includes a curvedcamming surface and the cross member is configured to cooperate with thecurved camming surface to assist retraction of the latchbolt into amortise box. In other embodiments, the anti-friction bolt has a U-shapedcross section, wherein the anti-friction bolt is pivotally coupled tothe solid latchbolt.

In still other embodiments, a latchbolt assembly includes a rod, a solidlatchbolt coupled to the rod, and an anti-friction bolt pivotallycoupled to the solid latchbolt. The anti-friction bolt includes a crossmember and a pair of plates depending orthogonally from the crossmember, with the cross member and plates cooperating to form a U-shapedcross-section. The anti-friction bolt is disposed to straddle the solidlatchbolt on three sides.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a prior art latchbolt;

FIG. 2 is an exploded view of an exemplary latchbolt according to thepresent invention;

FIGS. 3-9 are views of an exemplary anti-friction bolt for use with thelatchbolt of FIG. 2;

FIG. 10 is a section view taken along lines 10-10 of FIG. 11;

FIG. 11 is a section view taken along lines 11-11 of FIG. 10;

FIG. 12 is a section view taken along lines 12-12 of FIG. 11;

FIG. 13 is a top view of a mortise box with the exemplary latchbolt ofFIG. 2 disposed therein with the latchbolt in the fully extendedconfiguration; and

FIG. 14 is a top view of a mortise box with the exemplary latchbolt ofFIG. 2 disposed therein with the latchbolt in the partially retractedconfiguration.

DETAILED DESCRIPTION OF THE DRAWINGS

An exemplary latchbolt assembly 20 is shown in FIGS. 2 and 10-12. Thelatchbolt assembly 20 includes a tailpiece 22, a rod 24, a bushing 26, aspring 28, a solid one piece latchbolt 32, and an anti-friction bolt 34.The tailpiece 22, rod 24, bushing 26 and spring 28 are assembled into arod assembly 30 and coupled to the solid one piece latchbolt 32 asillustrated in FIGS. 10-11.

The anti-friction bolt 34 as illustrated in FIGS. 3-9 has a generallyU-shaped cross section. It includes a cross member 54 and a pair ofplates 56 depending orthogonally therefrom. The plates 56 include pivotpin apertures 60 for receiving pivot pins 58 as illustrated in FIG. 12.The cross member 54 includes a beveled edge 62

The solid one piece latchbolt 32 includes a base portion 36 having a rodassembly-receiving bore 38 and a retaining screw bore 42. The rodassembly 30 is operatively disposed in the rod assembly-receiving bore38 and a retaining screw 44 is operatively disposed in the retainingscrew bore 42 to engage the rod assembly 30, thereby retaining the rodassembly 30 in the base portion 36. The solid one piece latchbolt 32further includes a strike-engaging portion 46 that includes a curvedcamming surface 48 and a beveled camming surface 52.

The orthogonal plates 56 of the anti-friction bolt 34 extend parallel toand adjacent to the solid one piece latchbolt 32 as illustrated in FIGS.11-12. The plates 56 are pivotally coupled to the solid one piecelatchbolt 32 by pivot pins 58. Thus, the anti-friction bolt 34 isconfigured to straddle the solid latchbolt 32 on three sides asillustrated in FIG. 12. When pivotally coupled to the solid latchbolt32, the cross member 54 is configured to engage the curved cammingsurface 48 of the solid one piece latchbolt 32.

In operation, the latchbolt assembly 20 is conventionally installed in amortise box 64 as illustrated in FIGS. 13-14. The mortise box 64 isinstalled in a door edge and positioned to align the latchbolt assembly20 with a strike formed in a doorjamb in a known manner. As the door isclosed, the strike engages the leading edges of the orthogonal plates56, causing the anti-friction bolt 34 to pivot about the pivot pins 58.As the anti-friction bolt 34 pivots, the cross member 54 ofanti-friction bolt 34 engages the curved camming surface 48 of the solidlatchbolt 32, cooperating with the strike and the pivot pins 58 topartially force the latchbolt assembly 20 into the mortise box 64. Theanti-friction bolt 34 continues to pivot about the pivot pins 58 untilthe leading edges of the orthogonal plates 56 align with the beveledcamming surface 52 of the solid latchbolt 32. Once the leading edges andsolid latchbolt 32 are aligned, the strike cams against the solidlatchbolt 32 and the anti-friction bolt 34 to continue retracting thelatchbolt assembly 20 into the mortise box 64.

While a number of exemplary aspects have been discussed above, those ofskill in the art will recognize certain modifications, permutations,additions and sub-combinations thereof. It is therefore intended thatthe following appended claims and claims hereafter introduced areinterpreted to include all such modifications, permutations, additionsand sub-combinations as are within their true spirit and scope.

1. A latchbolt assembly comprising: a solid latchbolt having at least afirst surface, a second surface and a third surface; and ananti-friction bolt pivotally coupled to the solid latchbolt, theanti-friction bolt including a cross member disposed adjacent the firstsurface of the solid latchbolt and a pair of plates depending from thecross member, the plates being disposed adjacent the second and thirdsurfaces of the solid latchbolt.
 2. The latchbolt assembly of claim 1wherein the solid latchbolt includes a curved camming surface and thecross member is configured to cooperate with the curved camming surfaceto assist retraction of the latchbolt into a mortise box.
 3. A latchboltassembly comprising: a rod; a solid latchbolt coupled to the rod; and ananti-friction bolt having a U-shaped cross section, the anti-frictionbolt being pivotally coupled to the solid latchbolt.
 4. The latchboltassembly of claim 3 wherein the anti-friction bolt includes a crossmember disposed across the solid latchbolt, the cross member beingconfigured to engage the solid latchbolt.
 5. A latchbolt assemblycomprising: a rod; a solid latchbolt coupled to the rod; and ananti-friction bolt pivotally coupled to the solid latchbolt, theanti-friction bolt including a cross member and a pair of platesdepending orthogonally from the cross member, the cross member andplates cooperating to form a U-shaped cross-section, the anti-frictionbolt being disposed to straddle the solid latchbolt on three sides.